WTF! Did I just see!? A City in the Clouds leaves Thousands of Chinese left in awe as it appears above them

In what looks like a scene from a movie, tens of thousands of Chinese citizens were left in awe as what appeared to be a dilapidated stone city floating above them in the clouds appears, then 2 minutes later vanishes.

According to NASA their satellites also picked up what they called an anomaly. The two sentences describing what the satellites saw were quickly removed from their website within just 5 minutes of it being live. It is unknown if an optical illusion (which is what many claim it was) can be seen when viewed from satellites as well as by folks on the ground. Magicians familiar with this sort of illusion have said it cannot be, others have disputed the claims.

Are we being visited by Aliens? Is this an illusion? or is this a parallel universe?